@article {IOPORT.00635850,
    author       = {Culberson, Joseph C. and Reckhow, Robert A.},
    title        = {Covering polygons is hard.},
    year         = {1994},
    journal      = {Journal of Algorithms},
    volume       = {17},
    number       = {1},
    issn         = {0196-6774},
    pages        = {2-44},
    publisher    = {Elsevier, San Diego, CA},
    doi          = {10.1006/jagm.1994.1025},
    abstract     = {Summary: We show the following for polygons without holes: 1) covering the interior or boundary of an arbitrary polygon with convex polygons is NP- hard; 2) covering the vertices of an arbitrary polygon with convex polygons is NP-complete; 3) covering the interior or boundary of an orthogonal polygon with rectangles is NP-complete. We note that these result hold even if the polygons are required to be in general position.},
    identifier   = {00635850},
}